Transpolar Arcs and Hemispheric Asymmetry During Northward Interplanetary Magnetic Field (IMF)

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Understanding of the dynamics of the magnetosphere-ionosphere system, the coupling between the two regions, and its dependence on interplanetary conditions in particular, is of fundamental importance to almost every aspect of magnetospheric and ionospheric physics. In this project, electric and magnetic field and precipitating particle data from polar orbiting satellites such as DMSP F12, F13, F14 and F15, are used while the Polar UVI instrument provides measurements of auroral emissions. The SuperDARN radar array provides ionospheric convection maps. Ace, Wind, and IMP-8 provide solar wind velocity, density and interplanetary magnetic field (IMF) measurements. Time periods are utilized when Polar UVI provides a global view of the auroral distribution and at least two DMSP satellites measure particle properties, electric fields, and field-aligned currents in the upper ionosphere. Utilizing these data the understanding will be improved of the occurrence of trans-polar arcs (TPAs) and theta aurora in both hemispheres and the detailed plasma flows associated with them. In particular, the existence of high latitude TPAs is one of the most unusual features seen in the ionosphere and implies an unusual magnetospheric topology. The electrodynamics of TPAs is directly related to how coupling occurs between the solar wind-magnetosphere-ionosphere system during northward IMF. Analysis of the unique data set described will provide insight into simultaneous behavior and/or existence of TPA in both hemispheres and thus also into the topology of the magnetosphere.